Cold working apparatus and method



Feb, 19, 1957 c. A. NICHOLS EI'AL 2,781,678

COLD WORKING APPARATUS AND METHOD Filed July 17, 1952 v 4 Sheets-Sheet 1 7: v j INVENTORS (HA/Hi8 A. N/CH0L5 650805 I. Hf/Sf I y BILIIABD N. 6001mm Feb. 19, 1957 c. A. NICHOLS ETAL 2,781,678

COLD WORKING APPARATUS AND METHOD Filed July 17,l952 4 Sheets-Sheet 2 INVENTOR3 iazmgm Feb. 19, 1957 CQA. NICHOLS ETAL cow woaxmc APPARATUS AND METHOD 4 Sheets-Sheet 4 BY ME mun ATTOBNHJ Filed July 17, 1952 United States iano COLD WORKING APPARATUS AND METHOD Charles A. Nichols, Anderson, George L. Weiser, Middletown, and Richard M. Goodwin, Anderson, Ind., assignors to General Motors Corporation, Detroit, Mich, a corporation of Delaware Application July 17, 1952, Serial No. 299,316

4 Claims. (Cl. 8025) In carrying out this object, it is a further object tomount the fixture for the part to be rolled on yieldable' mounting which is operativelyassociated with the rolls,

said mounting being released just prior to the instant the rolls are taking hold of the part whereby the fixture moves into predetermined relation with respect to'the rolls for bringing the part to an exact position relativet-heret-o. In this manner, parts to be operated upon, which have had previous forming steps carried out thereon, are always positioned in the same relation to the rollsat the instant that the gap rolling operation is to be initiated.

A further object of the invention is to provide a gap rolling apparatus for forming compressor blades for example, wherein the blade has already been shaped to include a foot thereon whereby the rolls and the fixture for the blade are so associated that the rolls commence to.

form the blade in the same position with respect to the foot thereof in each operation of the rolls, whereby blades formed on said rolls are uniform with respect to dimen- In carrying out the above objects, it is still a further object to provide a fixture holder for the part to be rolled which is associated with the rolls by an operative connection thereto and which fixture is depressed against yieldable resistance during the initiation of operation of the rolls until the instant prior to the time that the rolls actually commence to deform the part tobe rolled .whereupon a latch is operatedwhich permits the yield-able: means to raise thefix-ture relative to the rolls into exact 1 position so that the rolling operation is always initiated at-a predetermined point withrespect to the dimensions.

of the part being operated upon.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein preferred embodiments of the present invention are clearly shown.

In the drawings:

Fig. 1 is a perspective view of the from the front thereof.

apparatus looking Fig. -2 is a partial sectional view of the gap rolls, fixture.

and ram at that point in the operation which is priorto the instant that the rolls commence to deform the part being rolled. 1

Fig. 3 is a view similar to Fig. l with some of thedetails removed, showing the work holder fixture in elevated position after the latch has been released.

fixture hasdropped downwardly.

"-"pressure, which cylinder acts against a work holding fix-.

v hereinafter.

2,781,678 Patented Feb. 19, 1957 Fig. 5 is a sectional view taken on line 5--5 of Fig. 2, showing the latch mechanism just prior to operation thereof.

Fig. 6 is a sectional view taken on line 6--6 of Fig. 3, showing the latch mechanism after operation thereof wherein the fixture holder has been partially elevated.

Fig. 7 is a view, in section, of the hydraulic cylinder and ejector used for ejecting the part from the nest of workholders.

Fig. 8 is a view, in perspective, of a partially formed compressor blade, being illustrative of one of the parts" which may be made in the apparatus and by the method I disclosed herein.

In copending application, Serial No. 270,073, filed February 5, 1952, a method and apparatus for cold forming fluid deflecting elements, such as turbo compressor. blades, is shown, wherein the initial formation of a blade from a metal blank is carried out by a gap rolling apparatus.

The present invention is directed to a second gap rolling step on an article, such as, a compressor blade, wherein wherein the article or blade to be gap rolled is moved by yieldable means into exact position prior to the actualgap rolling thereof so that each article made on the machine and by the method claimed is identical to the next. Referring specifically to the drawings, Fig. 1 shows a gap rolling apparatus 20 which is adapted to be associated with a punch press 22 which comprises a bed plate or im-v movable member 24 and a ram 26. The upper end of an actuator 28 is positioned in the ram 26 and cooperates with a pair of gap rolls 3i and 32, to be explained hereinafter, to move said rolls. Beneath the gap rolling apparatus 20 and integrally combined therewith is a double acting cylinder 34 carried by a supporting column 35 and adapted for attachment to a source of hydraulic ture 36 to hold the work piece 33, which in this instance, is a blade The cylinder 34 also includes an ejector means 40 which is automatically actuated as explained In Fig. 2, the gap rolling apparatus 20 is shown with the front plate removed therefrom sothat the rolls 30 and 32 are more clearly visible. In this instance, the

actuator 28 is provided with a rack 42 and a stepped pushing. device 44. The rack 42 cooperates with gears 46 and 48 positioned at the backside of the rolls 3i) and 32, re-

spectively, while the pusher 44 cooperates with stepped contour radial pushing devices 50 and 52 associated with rolls 3!] and 32, respectively. The radial pushing devices 50 and 52 and the stepped pusher 44 are used as gearingv means for turning the gap rolls towards one another. wherein high strength is required. In other words, we.

have found that gears alone do not have sutficient strength in the teeth thereof to withstand the pressures involvedv during rolling and, for this reason, the stepped pushers referred to are used. On the return of the gap rolling device 20 to starting position, as shown in Fig. 2., the gears 46 and 48 are utilized to bring the device into position.

The workholder workholder groove 60 so that the blade stands in an up 36 includes a groove or cut-out 60,, as shown in Fig. 7, which is of any convenient shape to right position. The airfoil section 62 has been partially formed by a previous operation and, in the gap rolling step, it is desired to further roll and thin out the airfoil section 62. For this purpose, it is important that .the suitably contoured gap rolls 30 and 32 commence totake hold of the airfoil section 62 exactly at the base portion 66 thereof so that each blade will be identicaL. In this connection, since the foot section 64 is not of a precision manufacture at this stage of operations, it is desirable to have the workholder 36 self-adjusting so as to bring the base portion 66 of the airfoil section 62 into exact engagement with the gap rolls at the instant that compression is initiated therebetween.

For this purpose, a latch mechanism 70 is provided. The latch 70 includes a detent 72 hingedly mounted to the rack 42 at 74. The holding fixture or workholder 36 is of a stepped design wherein a larger diameter is provided thereon at 76, which larger diameter carn'es a rubbing block 78 that cooperates with the detent 72 of the latching mechanism 70. Also cooperating with the detent 72 is a stationary latch plate 80 having a slanted surface 82 at the lower end thereof. The latch plate 80 is adjustably mounted to a portion 84 of the press by an eccentric headed bolt 86 which is held in position by nut 88. In this connection, when the nut 88 is loosened, the bolt 86 may be moved to rotate its eccentric head 90 and thereby move the latch plate 84) upwardly or downwardly to bring the slanted surface 82 into desired location with respect to the detent 72 of the latch 70 for adjustment purposes.

In operation, the work piece 38 is laced in the workholder notch 60 as shown in Fig. 2, whereupon the press is actuated to cause the actuator 28 to move downwardly. This causes the rack 42 to also move downwardly as well as the stepped pusher portion 44. This, in turn, causes the two gap rolls 30 and 32 to move towards one another in a downward direction and simultaneously causes the workholder 36 to move yieldably downwardly against the hydraulic fluid. The rolls do not engage the work piece 38 until the corner portions 92 and 94 actually bite into the metal of the work piece. Just prior to the time this occurs, the detent 72 slips 01f the rubbing block 78 due to the fact that the rear end of the detent 72 drops otf the latch plate 80. When this occurs, the hydraulic cylinder 34 causes the attached workholder to move upwardly due to fluid pressure being supplied through a port 95 to move the work piece upwardly so that the section 66 thereof bumps into the corners 92 and 94 on the gap rolls 30 and 32. This automatically self-adjusts the position of the work piece with respect to the gap rolls and as the actuator 28 causes the rolls to continue to turn in a downward direction, the work piece 38 is rolled therebetween.

At the end of the rolling operation, the workholder 36 has been moved downwardly against yieldable pressure exerted by the hydraulic fluid which enters the cylinder 34 through port 95. The source of this fluid may be provided with a suitable relief valve (not shown). When the blade in the workholder is free from the rolls, valving means (not shown) opens port 101 to release all pressure within the cylinder 34, causing the workholder 36 to drop downwardly due to gravity to its lower limit of movement as determined by stop 99 acting in slot 100 in support 35. During this drop, the lower end of piston 97 engages the upper end of piston 98 to cause the ejector pin 40 to be mechanically moved upwardly to eject the work piece 38 from the holder 36. At this time the press is reversed either manually or automatically and the rolls are then actuated to their starting position by upwardmovement' of the ram 26. Simultaneously, hydraulic fluid is caused to enter the port 95 through a suitable reversing valve to raise the workholder 36 to its initial position whereupon the latch mechanism will be automatically reset and the entire apparatus will be in readiness for the next operation.

It is apparent that in the functions described, the press and hydraulic cylinders, etc., may be actuated by hand or they may be provided with automatic reversing mechanisms electrically or mechanically controlled, such control devices forming no part of this invention.

It will be seen that the hydraulic cylinder 34 yieldably maintains the workholder 36 in an upward position at all times during rolling and that this workholder 36 is forced downwardly by the latch mechanism 70 until a position is reached just prior to the time that the gap rolls commence to compress the metal of the work piece. At the instant the latch releases the workholder, which is caused to move upwardly by the hydraulic cylinder 34, the gap roll corners are positioned firmly against the portion 66 of the work piece 38. In this manner, the workholder 36 is self-adjusting in that it alway brings the work piece 38 into the desired position with respect to the gap rolls regardless of dimensional discrepancies in the foot portion of the work piece. This isvery important since it eliminates inaccuracies in the cold-worked surface of the work piece as would be occasioned if the gap rolls took hold and started cold compressing the metal in different positions along the cold-worked surface thereof. This is especially true in connection with compressor blades for example, since the strength of said blades is a major item of importance and since a smooth contour of the airfoil section is of utmost necessity. Due to the self-adjusting nature of the device, every blade formed therein is identical, and in each and every case, the gap rolling step is initiated in the same exact position with respect to the blade due to the self-adjustment of the workholder when released by the latch mechanism 70.

While the embodiments of the present invention as herein disclosed, constitute preferred forms, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. In a gap rolling apparatus, the combination comprising; two gap rolls associated with one another for a rolling operation, a driving means for rotating said rolls, a workholder for holding work to be rolled by said rolls. yieldable means for urging said workholder toward said rolls and capable of yielding as the work is rolled, means for operatively connecting said driving means and work.-

holder for causing said workholder to move away from said rolls against said yieldable means during a portion only of the rotation of said work rolls and just prior to engagement of the rolls with the work, means operated by said driving means effective upon a predetermined movement of said workholder for releasing said operative connector means so that said workholder is free to move by action of said yielding means, and means on said rolls for stopping the last-named movement of the workholder to predetermine the start of a rolling action with respect to the work.

2. The gap rolling apparatus claimed in claim 1 wherein the workholder includes an ejector pin adapted to eject the work therefrom at the conclusion of the rolling operation, and means for operating said ejector pin, said lastnamed means being efiective only at the conclusion of said rolling operation.

3. A gap rolling apparatus, comprising in combination; two gap rolls associated with one another for rolling a work piece therebetween, a driving means associated therewith for rotating the rolls, a workholder for supporting the work piece, yieldable means supporting said workholder and resisting movement thereof, a latch for connecting the driving means and the workholder and for causing the workholder to move with the driving means during a portion only of the movement of the driving means as the gap rolls are being rotated, a release means operated by the driving means for unlatching the latch at the time that the rolls are about to bite into the work so that the workholder is free to move by the action of the yieldable means, and means on said rolls for stopping the last-named movement of the workholder to predetermine prising; two gap rolls, gears associated with each of said rolls, a rack cooperating with said gears for causing the rolls to rotate, driving means for moving the rack, a workholder for holding a Work piece to be rolled by said rolls, yieldable means for urging the workholder toward said rolls and capable of yielding as the Work piece is rolled, a connecting latch for connecting the rack and the workholder for causing the workholder to move away from said rolls against said yieldable means during a portion only of the rotation of the rolls and just prior to the engagement of the rolls with the work, means operated by said driving means and effective upon predetermined movement of the workholder for releasing the latch so that the workholder is free to move by action of said yieldable means, and means on said rolls for stopping the last-named movement of the workholder to predetermine the start of a rolling action with respect to the work piece.

References Cited in the file of this patent UNITED STATES PATENTS 

